1. Field of the Invention
This invention relates to a process and a system for destruction of hydrolysates, and particularly aqueous hydrolysates generated from the demilitarization of chemical munitions.
2. Description of the Prior Art
The destruction of chemical munitions is a major international concern. International treaties now outlaw these weapons, and their safe disposal has been mandated.
Disposal of chemical weapons is conventionally effected by means of incineration. Although incineration represents a technically feasible approach to the destruction of these materials, it is not only unacceptable to many state and local governments, but it is also unacceptable to many of the communities surrounding the stockpile sites. One of the major concerns of these groups is the perceived hazards to the environment associated with emissions from incinerators. There is a great desire on the part of all the stakeholders of the chemical munitions demilitarization process to find effective, safe and cost efficient alternative technologies for the destruction of these weapons.
Neutralization of the chemical agent and the energetic components of chemical munitions by hydrolysis in a strong base solution is an accepted alternative technology to incineration, but the treatment of the resulting hydrolysate is problematic because the hydrolysis products could be used to reform the chemical agent and thus must be further treated. Biological treatment processes are known to be able to successfully treat energetic hydrolysates as well as hydrolysates of mustard agent (H) but biological treatment of nerve agent (VX and GB) hydrolysates has proven difficult due to the low biodegradability of the carbon-phosphorous bond of the alkyl phosphonate component of these hydrolysates. For this reason, biological treatment of nerve agent hydrolysates in combination with energetic hydrolysates is not generally accepted as practicable. See Alternative Technologies for the Destruction of Chemical Agents and Munitions, NRC, which is incorporated in its entirety by reference, at p.126-136.
The present invention provides systems and methods that use a unique combination of oxidation, preferably UV/oxidation, followed by organic removal, preferably by biological treatment, to process chemical and energetic hydrolysates to achieve results that heretofore have not been attainable. The preferred processes comprise: (1) oxidizing a chemical hydrolysate, and preferably a hydrolysate comprising alkyl phosphonate, to produce a treated chemical hydrolysate containing organic compounds; (2) optionally combining the treated chemical agent hydrolysate with an energetics hydrolysate; and (3) removing at least a portion of the organic compounds contained in said treated hydrolysate by exposing said treated hydrolysate to biodegradation. The oxidizing step preferably comprises irradiating the chemical hydrolysate, preferably with ultraviolet (UV) radiation in the presence of an oxidant.
The present inventor has found that processes according to this invention are capable of achieving surprisingly and unexpectedly superior results when compared to the processes of the prior art. For example, the methods of the present invention are capable of removing alkyl phosphonates, a component found in many chemical agent hydrolysates, at a 90% or greater efficiency.